Participants will be subjected to baseline assessment which involves measuring resting surface EMG activity, muscle tone, stiffness, elasticity and pain. Then, subjects have to perform a computer task during 20 minutes while surface EMG activity will be measured every 5 minutes. After this computer task, all measurements will be repeated. After a resting period of 10 minutes, baseline measurements are repeated, followed by a computer task of 20 minutes and repetition of the same assessment. After this computer task, a single dry needling session of MTrP 2 of the upper trapezius will be performed bilaterally. During this treatment, surface EMG activity will be measured to captivate the EMG activity during local twitch responses.